Why do cables twist?

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During the production process, almost every multiwire cable in the audio and video sector is submitted to a stranding or laying direction to give the cable its compactness and bending properties. Multiwire cables are most often stranded in multiple layers.

Highly flexible cables are subject to an increased torsion strain, which will often take the stranded compound to its breaking limits. For technical reasons the stranding elements in the stranding layers are of different lengths and thus, of course, also subject to different strains, which is why in some multiwire cables the inner elements (such as the contact points at the connectors) will often tear first. A wire bundling would be ideal, which is, however, not possible in certain cases (e.g., with 4- or 8-wire speaker cables), because the cables would become too thick and too cumbersome then.   

If the cable is forced into an unnatural position by an extreme or reverse bend and at the same time exposed to tensile forces, the individual wires may ”jump“ out of their guides and cannot slide back any more. The result is a formation of knots or cable twisting. Gluing cables together with other cables is not recommended either, because a ”jam“ can occur just as easily in this constellation, since the wires within the stranded bundle cannot relax.

Some cable makers think they can avoid the problem by simply injecting a thicker outer jacket in the extrusion process as a means of protection for the inner elements – provided the overall diameter allows it. But this will only shift the problem into the cable interior, because instead of the overall construction the individual wires will now twist and tear.

Sommer cable has employed a new, zero torsion stranding method (X-Torsion) for quite some time which handles this problem very well. Yet the case of improper handling the formation of knots cannot be avoided completely. Please make sure to relax cables prior to reeling or to lay them out full length before reeling them onto a cable drum.